Direction changing drilling device



Nov. 17, 1936. J, BRACK DIRECTION CHANGING DRILLING DEVICE Filed June 24, 1936 INVENTOR Ja/m fl. flral/li MM ATTORNEYS Patented Nov. 17, 1936 UNITED STATES PATENT OFFICE John' D. Brack, Sulphur, La., assignor, by direct and mesne assignments, to LouisianaSupply Company, Sulphur, 'La., a corporationoi Delaware Applicationlune 24, 1936. Serial No. 86,941

9 Claims. (Cl. 255-1) The invention relates to rotary earth drilling whipstock is a rather tedious operation for the and more particularly to a device used in changreason that the length of .the bore that can be ingthe direction of the bore of a well being drilled in the new direction is limited. It is drilled. therefore necessary to withdraw the whipstock In rotary earth drilling it is sometimes desirand insert a smallbit of the same size as the bit able to change the direction in which ahole, is used with the whipstock and continue the drilling. being drilled. For example, it may be intended in the new direction. This small bit is then that a hole should proceed in a certain direction removed and a pilot bit is inserted, which enwhen actually it is proceeding at an angle to largesthe hole to the full size. It is therefore 1 that direction; in this event it is necessary to apparent that it is necessary to make three trips change the bore of the hole to its originally inin and out of the well. Inasmuch as each trip tended direction. In other cases after drilling requires the removal of the entire drill stem, it in a given direction it may bedesirableto change will be appreciated that this is an expensive opthe direction of a hole in order to avoid certain eration and that it would be economically advanformations or to lead to other formations. tageous to be able to change the direction of the In changing the direction of the hole, it is well with only one trip. immaterial in what direction the new direction It is therefore an additional object of my inof the'hole is to proceed, the operation is generally vention to provide a device with which theamount referred to as sidetracking. If it is desired a of drilling that may be done in any given direction 0 that the hole should proceed in, any-given direction, the operation is generally referred to as die rectional drilling."

The principal object of my invention is to pro-w; vide' a device which may be used in changing the;

direction of the bore of a well, either in a side-, tracking or directional drilling operation.

Heretoiore when it has been desired to change the direction of a well by a sidetracking opera tion, an apparatus known asa knuckle joint has been generally used. .Whenit has been desired to give the bore particular direction, it has been customary to employla whipstock. Inasmuch as my direction changing device may be used in either a sidetracking or directional drilling operation, it may be used to accomplish both of the operations now accomplished by'two tools, namely, the knuckle joint and the whipstock.

' The knuckle joint comprises a drilling member held at an angle to the drill stem by means of o a universal joint. Through this joint the drilling fluid is forced under pressure. Inasmuch as it is extremely difficult to maintain such a universal joint under the high pressures to which the drilling fluid is normally subjected, considerable 5 difliculty is experienced in keeping the tool in repair.

It is an object of my invention to provide a device in which the drilling fluid does not pass through a movable joint, and therefore with my device no difliculty is experienced due. to wear of the parts or leakage of the drilling fluid.

A whipstock which is generally employed in di rectional drilling, has an inclined surface which deflects a relatively small drill as it proceeds as downwardly. Directional drilling by means of a stantially the'same size as that formed by an ordinary drill and with which it is unnecessary to make more than one trip. in and out of the well to accomplish a given change in direction.

In the operation of a-whipstock the small bit turning against the inclined face of the whipstock tends to "roll oil this face in a lateral direction, and it is therefore customary to set the whipstock at an angle of about 20 from the direction that it is intendedthe new bore should take in order to compensate for this "roll oif". Inasmuch as the amount of "roll on will vary with, the type of formation being drilled, it is diflicult to determine the exact angle at which the new direction of the bore will take.

It is a further object of my invention to'overcome this difllculty and to provide a device which may be set at-the desired, angleand the bore given a new direction which is the same as that at which the device is set without necessitating an allowance forany indefinite factors.

When it is desired to have the bore proceed in a new direction beginning at a point other than .atrthe bottom of the well, it is common to cement a "plug in the well at a point where it is desired the bore should be given the new direction. The directional drilling device is then lowered to this plug and the new direction of the bore extended from this point. In cementing a plug in a well there is generally a soft annular ring between the plug and the wall of the bore, due to thefact that the cement does not harden properly in this outer annular space. When a whipstock is used to "get ofi-the plug it is common for the small bit used with the whipstock to follow through is unlimited, with which thehole formed is sub.

this soft annular space between the plug and the wall of the bore and proceed in the direction of the old hole rather than to be given a new direction.

As an additional object of my invention, I provide a device by means of which the direction in which the drill proceeds is positively controlled and cannot deviate due to any particular structure in the formation; therefore no difiiculty is encountered in getting off a plug".

It is also an object of my invention to provide a device in which the shear pin, which fastens the drill directing means to the drill and drill stem, cannot shear until the tool is accurately located in position.

A further object of my invention consists in the provision of a device which can be withdrawn from the well as a unit when the direction changing operation is complete.

And as an additional object of my invention, 1 provide a device comprising a loose joint by means of which the rotation of the drill stern may be transferred to a drill which is rotating about an axis at an angle to the axis of the drill stem.

My invention has other objects and the device has other advantages and includes other features of novelty in addition to those mentioned, as will be apparent from consideration of the following description and the accompanying drawing.

The device comprising my invention consists essentially of a central shaft held in a non rotatable position at the bottom of the well or held on a plug. The upper portion of the shaft has an axis parallel to the axis of the drill stem and the bore, and the lower portion of the shaft is inclined so as to have an axis at an angle to the bore. Around this inclined portion of the shaft is mounted a drill which rotates about this portion of the shaft. The drill, therefore, is forced to proceed at an angle to the axis of the bore. The drill is connected to the drill stem by a loose joint which transfers the rotation of the drill stem to the angularly positioned drill.

The invention will be more fully understood from a consideration of the accompanying draw ing showing an embodiment of my invention, and in which:

Figure 1 shows a view, partly in vertical section and partly in elevation, showing the complete device;

Figure 2 is a cross-section on line II-l1 of Figure 1;

Figure 3 is a cross-section taken on line III-III of Figure 1;

Figure 4 is an elevation of the drill associated with the lower portion of the direction changing member;

Figure 5 is an elevation, showing certain parts in vertical section, of a modification of the device having lateral projecting arms.

The lower portion of the-drill stem l is provided on the interior thereof with a shoulder 2. A coil spring 3 is positioned so that its upper end is adjacent the shoulder 2 and its lower end is adjacent an upper wear plate 4. A lower wear plate 5 is separated from the upper wear plate 4 by ball bearings 6 so that the drill collar I, the spring 3 and the upper wear plate 4 may rotate with respect to the lower wear plate 5. The lower wear plate 5 rests upon an extension 1a of a central shaft 1. Threaded to the lower portion of the shaft 1 is a fork 8 having points 9 adapted to be engaged in the bottom of the formation or in a plug in the bore. When the fork is so engaged the shaft 1 is held in a non-rotatable position.

It will therefore be seen that if a downward force is imparted to the drill stem, this force will be transmitted through the shoulder 2, the spring 3, the wear plates 4 and 5 and the shaft 1, and the points 9 of the fork 8 will be forced into the formation. The spring 3 is relatively strong so that a considerable pressure can be applied to the fork 8 as the spring is being initially compressed.

The drilling fiuid which is forced down through the center I2 of the drill stem I passes through the hollow center I3 of the shaft 1 and exits at the opening I4 in the fork 8. Threaded to the lower portion of the drill stem l is a stufflng box I5 into which is threaded a packing gland I6. Between these two members is suitable packing material I1 which engages the exterior of the shaft 1 and prevents the fluid from moving downwardly except through the opening I3 in the shaft I. Concentric packing rings II are mounted on the extension 1a of the shaft 1; these rings engage the interior of the drill collar I, and also act to prevent the fluid from flowing downwardly outside the shaft 1. In view of the packing I1, the packing rings II may be omitted, if it is desired.

Threaded to the outside of the stuffing box I5 is a collar I8 having at its lower end an extending shoulder IS. The collar I8 is therefore rotated with the drill stern l, and by means of the collar 20, this rotation is transferred to the drill 21. The structure by which this is accomplished includes keys 2I mounted on the interior of the collar 20, which keys fit into keyways 22 in the shoulder iii. In the upper portion of the collar 20 are screws 23 which extend beyond or overlap the shoulder IS. The collar I8 and the collar 28 may move vertically relative to each other. This movement is limited by the contact of the lower surface 24 of the shoulder IS with the shoulder 25 of the collar 28 and the contact of the upper surface 28 of the shoulder is with the screws 23.

. The drilling means comprises an annular drill 21 having three radially extending cutting members 28. The lower portion of the drill is recessed to form an opening 29 so that the lower portion 3| of the drill may overlap the fork 8 as the drill moves downwardly. Cutters 38 are provided on the lower end of the drill. The upper portion of the drill is provided with a shoulder 32, similar to the shoulder I8, into which shoulder are formed keyways 33, similar to keyways 22. Keys 34 are formed on the lower portion of the collar 20, which are similar to keys 2 I, and screws 35, which are similar to screws 23, are also mounted on the collar. It is apparent that the connections on the upper and lower portions of the collar are similar and that the drill 21 may move vertically relative to collar 20. This movement is limited by the contact of the upper surface 36 of the collar 32 with the surface 31 of the collar 28 and the contact of the lower surface 38 of the shoulder32 with the screws 35.

The shaft 1 is bent at a point about midway between its ends so that the drill 21, in turning about the lower portion of the shaft 1, turns about an axis which is at an angle to the axis of the upper portion of the shaft 1, and the drill stem.

This angle may be any amount and will be determined by the amount of deflection it is desired to secure. An angle of 5 is a convenient angle, but larger or smaller angles may be used, for example angles up to A shear pin 38 which is adapted to break upon the application of predetermined pressure, connects the drill 21 with the shaft 1.

When the device is to be used for sidetracking it is lowered into the well in position so that the angular portion of the shaft 1 projects in any direction. However, when the device is to be used in directional drilling, the well is first surveyed and the device is then surveyed into the hole so that the angle of the shaft 1 is extending in the proper direction. When the device has reached the bottom of the bore, ora plug, and weight or pressure is applied to the drill stem I, the spring 3 is compressed and this force is transmitted through the wear plates 4 and 5 ahd the shaft I, to the fork 8, forcing the points 9 into the formation or the plug. As the drill stem is moved downwardly and the spring is compressed, the

collar I8 is also moved downwardly. when the surfaces 24 and 25 contact each other, the collar 20 is moved downwardly and when the faces 36 and 31 contact each other, the drill 21 is then moved downwardly and the shear pin 39 is broken. At this time the force applied to the points 9 is sufficient to project them firmly into the formation and hold the shaft 1 in a nonrotatable position.

If the drill stem is now rotated, this rotation is transmitted through the stuffing box ll, the collar l8, the keys l9, the collar 20, the keys 34,-to

the drill 21. As the drill moves downwardly during this rotation. the cutters 28 cut away the side of the formation and the cutters 30 contact and cut the bottom of the formation. During this time greater pressure is beingapplied to the spring and the force urging the points 9 into the formation is greatly increased. As the cutters 30 remove the formation surrounding the points 9, the fork 8, due to the great pressure of the spring, is projected further into the formation; and the portion of the formation between the points 9 is washed away by the'fluid exiting-from the opening i4.

The points 9 continue to be urged in the same direction and the shaft I is held in the original direction in which it is secured. The drilling may be continued in the same direction until the desired amount of deflection is obtained.

When the device is to be withdrawn from the hole, the drill stem l is raised and the surface 26 contacts the screws 23, raising the collar 20. The screws 35 then contact the surface 38 and the drill 21 is raised. The annular shoulder on the stumng box l5 contacts theshoulder'50 on the shaft 1, and in this manner the shaft I is raised, withdrawing the fork 8 from the formation. The entire assembly is therefore removable as a unit. After the direction of the hole has been changed and the device is withdrawn from the well, an ordinary bitmay be inserted and drilling may proceed in the usual manner. It will be apparent that the new hole proceeding -in the different direction will have substantially the same diameter as the original hole so that it is not necessary to ream the hole prior to further drilling operations.

The joint between the collar l8 and the collar 20 and the joint between the collar 20 and the drill 21 are referred to as loose joints, for the reason that they not only act as a universal joint in translating the rotation about one axis into rotation about an axis at an angle thereto, but also transmit vertical force and permit a vertical lost motion which is desirable in the operation of the device.

The shear pin 39 cannot be broken until the fork 8 is securely fastened in the formation. If the drill 21 strikes an object as the device is being lowered intothe well,- and force must be applied to pass this object, the drill is not moved relative to the shaft 1 and the pin is not broken. There,

is no relative vertical .movement between-the shaft 7 i and the drill Zluntilthe spring 3 is compressed,

and this action does not take place until the fork v 5 contacts the formation. I

, The drill 21 cannot belost inasmuch as the shoulder 5| on the drill 2'! overlaps the shoulder Won the fork 8. Should the screws 35 become broken, the drillwould be removed by the contact two arms 45 and 46, which are pivoted together. I

at 4'l. The outside edges 48 of the arms 45 and 46 are provided with sharp edges, which cut into the wall.. of the formation. Suitable bearings, such as roller bearings 49, are provided, in order to permit the drill and the collar to rotate relative to the arms 45 and 46. The length of the arms is such that as the ,device is being lowered into the well, they are held in a vertical line adjacent the collar 20. However, after the device islowcred and force. is applied to the drill stem, these armsare'extended laterally so as to contact the side of the wall. As the drill is lowered the sharp edges 48 cut avertical groove in the wall and this groove tends to proceed in a straight line down the side of the wall as the drilling proceeds. The lateral force of these :arms causes the device to proceed in the right direction and relieves some of the strain on theshaft I. The vertical groove in which the arms 45 and 46 descend also assists in-preventing the bore from changing direction as it progresses. The arms 45 and 46, while desirable under many circumstances, are not essential and the device, as shown in Figure 1, may be very satisfactorily operatedwithout them.

It will be obvious that many. other modifications of the embodiment illustrated in the'speciflcation and accompanying drawing may be made withoutdeparting from the spirit and scope of the invention, as defined in, the following claims.

I claim: g

1. In a device for changing the direction of a well, a rotatable drill stem, elongated means having the longitudinal axis thereof at an angle to the longitudinal axis of the drill stem and the well, formation engaging means at the bottom of the elongated means adapted to hold the same in a non-rotatable'position, a drill rotatable about the axis of said angularly positioned elongated means, means for transferring the rotation of the drill stem to the drill, whereby the drill proceeds at an angle to the axis of the drill stem and the well, and resilient means for applying a downwardaxial force to said elongated means during the rotation of said drill to urge the formation engaging means into the formation as the drilling the direction of a drill stem and thewell and a lower portion having an axis at an angle to said axis, of the drill stem and the well, a drill mounted to rotate about said lower portiomand a loose joint for imparting the rotation of the drill stem to said drill well, a rotatable drill stem, elongated means secured to said drill stem so that the longitudinal axis of the elongated means projects at an angle to the longitudinal axis of the drill stem and the well, severable means operatively connecting said elongated means and said drill stem whereby rotation may be imparted to said elongated means by said drill stem and the direction in which the elongated means projects may be controlled by the rotation of said drill stem, formation engaging means on said elongated meansadapted to hold the same in a non-rotatable position upon severing of said severable means, a drill encircling-and rotatable about said angularly positioned elongated means, and means for transferring the rotation of the drill stem to the drill, whereby the drill proceeds at an angle to the axis of the drill stem and the well.

5. In a device for changing the direction of a well, a rotatable and axially movable drill stem, elongated means having a longitudinal axis at an angle to the longitudinal axis of the drill stem and the well, formation engaging means at the lower end of the elongated means adapted to engage the formation at the bottom of the well and hold said elongated means in a nonrotatable position, a resilient means for applying a downward force to said elongated means when said drill stem is moved axially whereby said formation engaging means is urged into theangle to the axis of the drill stem and the well.

6.1a a device for changing the direction of'a well, a rotatable drill stem, a central shaft having an upper portion parallel to the axis of the drill stem and the well and a lower portion having an axis at an angle to said axis of the drill stem and the well, formation engaging means at the bottom of said shaft, a resilient means adapted to transmit vertical force from said drill stem through said shaft to said formation engaging means, a drill mounted to rotate about said lower portion of the shaft, and a L In a device for changing the direction of a 7. In a device .for changing the direction of a 7 well, a rotatable drill stem, a stop on the interior of said drill stem, a central shaft having an upper portion parallel to the axis of the well and a lower portion at an angle thereto, a spring interposed between said stop and said shaft, formation 0 8 8 8 means on the lower end of said shaft, a drill mounted to rotate about said lower portion, and a loose joint connecting said drill stem to said drill for transmitting the movement of the drill stem to said drill, whereby a vertical force on said drill stem compresses said spring and urges said formation engaging means into the formation and causes said drill to move relative to said shaft along an axis at an angle to the axis of the well.

8. In a device'for changing the direction of a well. a rotatable drill stem, a central shaft having an upper portion parallel to the axis of the drill stem and the well and a lower portion having an axis at an angle to said axis of the drill stem of the well, formation engaging means at the bottom of said shaft, a resilient means adapted to transmit vertical force from said drill stem through said shaft to said formation engaging means, a drill mounted to rotate about said lower portion of the shaft, ashear pin connecting the drill to the shaft and adapted to be broken when said formation engaging means is urged into position, and a loose joint for imparting the rotation of the drill stem to said drill.

9. In a device for changing the direction of a well, a rotatable drill stem, a collar on the interior of said drill stem, a central shaft having an upper portion parallel to the longitudinal axis of the drill stem and the well and a lower portion at an angle to the longitudinal axis of the drill stem and the well, a bearing at the upper end of said shaft, formation engaging means at the bottom thereof adapted to'hold said elongated means in a non-rotatable position, a resilient means between said collar and said bearing adapted to transmit vertical force from the-drill stem to said shaft and formation engaging means, a drill rotatable about said lower portion of the shaft, a shear pin connecting said drill to said shaft and adapted to be broken when said formation engaging means is in position, and means for translating the rotation and the longitudinal movement of the drill stem into rotation and longitudinal movement of said drill, whereby said drill proceeds at an angle to the axis of the well.

JOHN D. BRACK. 

